Negative electrode material and non-aqueous electrolyte secondary battery

Abstract

Disclosed is a negative electrode material including: a lithium silicate phase that contains a lithium silicate; and silicon particles that are dispersed in the lithium silicate phase, wherein the silicon particles have a crystallite size of 10 nm or more, and the lithium silicate has a composition represented by the following formula: Li 2 Si 2 O 5 .(x−2)SiO 2 , where 2<x≤18 is satisfied.

The invention claimed is: 
     
       1. A negative electrode active material comprising:
 a lithium silicate phase; and 
 silicon particles that are dispersed in the lithium silicate phase, 
 wherein the silicon particles have a crystallite size of 10 nm or more, 
 the lithium silicate phase has a composition represented by the following formula: Li 2 Si 2 O 5 ⋅(x−2)SiO 2 , where 2<x≤18 is satisfied, and 
 wherein the negative electrode active material is a particulate material. 
 
     
     
       2. The negative electrode active material in accordance with  claim 1 ,
 wherein 2.1≤x≤18 is satisfied. 
 
     
     
       3. The negative electrode active material in accordance with  claim 1 ,
 wherein 3≤x≤8 is satisfied. 
 
     
     
       4. The negative electrode active material in accordance with  claim 1 ,
 wherein the lithium silicate phase and the silicon particles form the particulate material, and the particulate material that has an average particle size of 1 to 25 μm. 
 
     
     
       5. The negative electrode active material in accordance with  claim 4 , comprising
 a conductive material that covers at least a portion of a surface of the particulate material. 
 
     
     
       6. The negative electrode active material in accordance with  claim 1 ,
 wherein the silicon particles have an average particle size of 500 nm or less. 
 
     
     
       7. The negative electrode active material in accordance with  claim 6 ,
 wherein the silicon particles have an average particle size of 200 nm or less. 
 
     
     
       8. A non-aqueous electrolyte secondary battery comprising:
 a negative electrode that includes the negative electrode active material in accordance with  claim 1  and a binder; 
 a positive electrode that is capable of electrochemically absorbing and desorbing lithium; and 
 a non-aqueous electrolyte.